I think you're probably right, it is more lack of life experience, but that makes her come off as seeming quite dim at times to me.
Rather than admiring the tenacity with which she'll stick to an argument I find myself shaking my head at how incredibly naive she sounds.
You're right though, might just be lack of life experience.
I would have hoped she'd managed to pick up a little by her late 20's though.
It's not like she's a teen.